IRBIL, Iraq (Reuters) - The U.S. defense secretary has visited Iraq's Kurdish region to help defuse tensions with the central government over land and oil that U.S. and Iraqi officials fear could spill into violence.

Defense Secretary Robert Gates met Masud Barzani, former guerrilla leader and president of Iraq's largely autonomous Kurdish region, whose Irbil-based Kurdistan Regional Government is at odds with Baghdad's Arab-led government.

The dispute over land, hydrocarbons, and power between Kurdistan in Iraq's north and the central government in Baghdad has ratcheted up, leading to fears of possible clashes between Iraqi troops and Kurdish Peshmerga forces.

There are fears that Iraq's waning insurgency might style itself as an Arab bulwark against Kurdish encroachment.

U.S. Army General Ray Odierno, the top U.S. commander in Iraq, on July 28 called the dispute the "number one driver of instabilities" in the country.

The Pentagon did not immediately provide an account of the talks between Gates and Barzani.

Gates, who landed in Iraq on July 28 on a previously unannounced visit, offered U.S. help in resolving disputes over Kurdish claims to disputed territories.

"We are...willing to assist in resolving disputes over boundaries and hydrocarbons, disputes that require continued commitment to the political process by word and deed," he said.

Gates' visit comes as Iraqi officials prepare to announce the results of weekend presidential and parliamentary polls in Kurdistan which, despite an unprecedented challenge from opposition groups, are seen as unlikely to unseat Barzani from the presidency and shatter his allies' grip on power.

There is some hope that Iraqi and Kurdish officials may be more ready to make concessions now that Kurdish electioneering, characterized by fiery rhetoric about disputed areas, is over.

At the heart of the feud is the oil-producing region of Kirkuk, which Kurds consider their ancestral homeland and want to make part of their semi-autonomous Kurdish enclave. The city's Arabs and Turkmen fear Kurdish hegemony.

In preliminary results released on July 29, opposition groups made a surprise gain, but ruling parties entrenched in a feud with Arab leaders in Baghdad clung to power and were unlikely to drop their main demands.

A reform-minded opposition movement, Change, took a surprise 23.8 percent of the parliamentary vote, but complained of fraud and aggression from the region's ruling two-party alliance.

"These figures contradicted the real will of the Kurdish people and were the result of organized forgery...by the two parties in power," senior Change member Shamal Abdulla said.

Barzani's Kurdistan Democratic Party (KDP) and Iraqi President Jalal Talabani's Patriotic Union of Kurdistan (KDP) took 57 percent of the parliamentary vote.

"We are happy with these preliminary results and with the success of this election. It is a proud day for our people," KDP official Jaafar Ibrahim said.